Clomiphene citrate (CC) and metformin are two effective drugs used to induce ovulation in patients with polycystic ovary syndrome (PCOS), even if it is still unclear which compound between them should be initially administered. The aim of the study will be to compare in a clinical setting the efficacy of CC and metformin as first-line approaches for treating anovulation in infertile PCOS patients.

Eighty infertile anovulatory patients with PCOS will be allocated in two body mass index (BMI)- and age-matched groups (experimental and control groups).

Forty patients will receive the experimental treatment consisting of six months of 1700 mg/day metformin administration (experimental group), whereas other forty patients will receive CC administered using a traditional incremental-doses protocol (control group). In both groups, patients who will ovulate under treatment will continue the therapy for a total of six months.

During the study, the clinical and reproductive outcomes, and the adverse experience will be evaluated in each patient.

Inclusion Criteria:

• Anovulatory infertility related to polycystic ovary syndrome

Exclusion Criteria:

• Neoplastic, metabolic, hepatic, and cardiovascular disorders or other concurrent medical illnesses
• Hypothyroidism, hyperprolactinemia, Cushing's syndrome, and non-classical congenital adrenal hyperplasia
• Current or previous (within the last six months) use of oral contraceptives, glucocorticoids, antiandrogens, ovulation induction agents, antidiabetic and anti-obesity drugs or other hormonal drugs.
• Organic pelvic diseases
• Previous pelvic surgery
• Suspected peritoneal factor infertility
• Tubal or male factor infertility or sub-fertility